The present disclosure relates to a display-type optical sight device, and more particularly, to a display-type optical sight device whereby a video image including aiming information is displayed together with an aim indicator (reticle) in the state in which parallax is corrected, so that asthenopia caused by repetitive accommodation of the eye(s) can be prevented.
Aiming a gun is achieved by visually aligning a front sight and a rear sight. Aiming by visually aligning the front sight placed at an end of a gun barrel and the rear sight placed at an upper portion of a main body of the gun enables precise shooting depending on the skill of a shooter of the gun. However, visual alignment is difficult due to even small vibration or shaking, and rapid aiming required at a near distance or in an urgent situation cannot be easily performed. That is, such an aimed shooting method requires complicated procedures and time to acquire and ascertain a target, align the sights, aim at the target, and the like. Since the front sight and the rear sight themselves are very small, not only are they susceptible to even a minor shaking, but also the shooter's eye(s) turns upon the front sight and the rear sight rather than at the target or a forward situation. Therefore, a field of view becomes narrow when the shooter pays too much attention to sight alignment in order to accurately align the front sight and the rear sight.
Thus, an optical sight device has been proposed to improve upon the above cumbersome sight alignment and further improve accuracy. However, since a telescopic lens is used in the optical sight device, when magnification increases, the optical sight device is susceptible to even minor shaking, so that it is difficult to perform rapid aiming.
In order to address this problem, an optical dot-sight device in which a non-magnifying (low-magnification) lens may be employed and only a simple dot of sight is used instead of complicated sight alignment.
Simple and quick aiming may be possible with an optical dot-sight device. Also, it is advantageous for quick aiming at a short distance or in an urgent situation. In other words, it takes little time to align the line of sight, aiming is performed by rapidly aligning a dot that is a virtual image of a light point formed from a mask or a projection reticle placed in front of a light emitting diode (LED) with the target, and a wide field of view may be obtained. Therefore, the optical dot-sight device has advantages of minimizing time required for aiming and disturbance of a peripheral field of view and situation verification caused by aiming.
As illustrated in FIG. 1, an optical dot-sight device 1 includes an adjuster 7 that is placed on a top of a cylindrical sight housing 2 and used to align an internal tube body, a fixing grill 26 that is placed on a bottom of the sight housing 2 and detachably coupled to a rifle rear sight module by a rail, a protective window 10 placed at a front end of the sight housing 2, a light-emitting device 8 (LED or a laser diode (LD)) that is placed at a predetermined position inside the tube body within the sight housing 2 and emits light as a light source, and a reflector 9 having a certain radius of curvature and placed behind the protective window 10 within the sight housing 2.
The reflector 9 reflects beams emitted from a light point of the light-emitting device 8 toward an observer (user). A dot that is a virtual image of the light point is placed at the position of a target.
The observer (user) shoots when the dot that is the virtual image of the light point of the light-emitting device 8 and the target are aligned with each other, and thus aiming can be easily performed.
Theoretically, it is intended that beams emitted from the light point formed by the light-emitting device 8 placed inside the optical dot-sight device 1 are reflected by the reflector 9 and enter the observer's eye(s) nearly in parallel and in alignment with a bullet shooting axis of the gun barrel. However, if the axis of the optical dot-sight device 1 is not aligned with the bullet shooting axis of the gun barrel, the target is missed, even though the observer aligns the dot that is the virtual image of the light point of the light-emitting device 8 with the target. Thus, in order to align the axis of the optical dot-sight device 1 with the bullet shooting axis of the gun barrel, the adjuster 7 for aligning the internal tube body having elevation and windage adjustment functions is provided to align the optical axis of the inner tube body with the bullet shooting axis of the gun barrel.
The reflector 9 reflects the beams emitted from the light point of the light-emitting device 8 toward the observer (user). The dot that is the virtual image of the light point is viewed to overlap the position of the target. A transmission-type liquid crystal display (LCD) display window is installed at a certain position of the reflector 9 by disposing transparent electrodes so as to display information required for shooting, such as a wind speed, a degree of inclination of a current area, and information regarding an enemy, in addition to the light point. In this case, since a point of fixation (or an object of regard) of the observer's eye(s) is not aligned with the position of the dot that is the virtual image of the light point in the light-emitting device 8 and the position of an image of a window for displaying information installed at the reflector 9, the observer (user) has to accommodate his/her eye(s) so as to verify the image of the window while seeing the dot that is the virtual image of the light point and the target.
However, repetitive eye accommodation causes accommodative fatigue or asthenopia. Thus, a method using the window for displaying information attached to the reflector 9 causes the user's eye(s) to easily become fatigued, and causes the speed of shooting on the target to be lowered when the optical sight device is used for a long duration. Also, the dot-sight device employing the method and other dot-sight devices that have been developed to date use a method in which it is difficult to change the shape of the light point according to the size of the target and the distance to the target.